1. Field of Invention
The embodiment of the present invention relates generally to a circuit structure and, more particularly, to a damper circuit.
2. Description of Related Art
Recently, the compact fluorescent lamp (CFL) and the light emitting is diode (LED) are increasingly being used in lighting applications due to their higher energy efficiency and longer life than the incandescent lamp.
As is well known, a phase cut dimmer is often used with an incandescent lamp to realize a dimming function. However, a normal lamp driver can not operate correctly with a phase cut dimmer. If a normal lamp driver is connected to a phase cut dimmer, the lamp will flicker.
In order to replace an incandescent lamp with a CFL or LED in a phase cut dimming system, this problem should be solved. The reason for this problem is that a TRIAC (triode for alternating current) in a phase cut dimmer requires a minimum holding current to maintain in a conductive state after it is triggered, but the resonance of an electromagnetic interference filter in a normal lamp driver at the rising edge of an input voltage will make the current through the TRIAC lower than the required holding current value, causing the lamp to flicker.
In order to solve the above problems, those skilled in the art are striving to find a solution, but no applicable method has yet been put forward. Therefore, there is a need to improve the resonance of electromagnetic interference filters resulting in a flicker of a lamp due to a change of the current through a triode for alternating current switch when the phase dimmer activates.